OLED (Organic Light-Emitting Diode) display is a kind of all solid state, active light emitting display. OLED display has the characteristics of high brightness, high contrast, ultra thin and light, low power consumption, unlimited visual angle range, wide working temperature range and so on, therefore it is considered as an emerging next generation display.
Active matrix OLED (AMOLED) display panel is very different with thin film transistor liquid crystal display (TFT-LCD) in the product characteristic. At present, for the development of the AMOLED display technology, a particularly prominent problem is the image sticking. The image sticking is related to the contour of the displayed image. Different displayed gray scales will cause a great difference between the drain currents of driving thin film transistors; meanwhile, the difference between the gate-source voltages (Vgs) of respective thin film transistors (TFT) causes different effects of voltage stress on respective thin film transistors; therefore, on the screen, different TFT threshold voltage (Vth) drifts may be generated for OLED pixels on the display, having a contour of the displayed image.
In addition, after a long-term use, the electro luminescent material of the OLED display will be aged, reducing the light emitting efficiency. This will also cause the image sticking of the OLED display.